This invention relates to surface treating agents for treating surfaces of glass, glass lenses, mirrors, plastics, plastic lenses, metals, ceramics, porcelain and earthenware to form antifouling coatings which are tack-free, non-adherent to dust and debris, and repellent to both water and oil. It also relates to articles treated with the surface treating agents.
It is known in the art to coat optical lenses such as eyeglass lenses and camera lenses with layers of cured silicone and/or fluorocarbon polymers in order to impart antifouling property and water repellency to the lenses. The treating agents proposed thus far to this end are typified by trifunctional organosilicon compounds such as C8F17C2H4SiCl3 and C4F9C2H4Si(NH)3/2 or partial hydrolyzates thereof as disclosed in JP-A 60-221470.
When substrates are treated with such trifunctional compounds alone, the surface is covered with only a polymer having a three-dimensional structure so that the surface remains flexible or rather tacky. Undesirably, dust and debris will adhere to such surface, and fingerprints resulting from hand touch are left stuck thereto.
Then JP-A 11-116809 and JP-A 11-116810 propose surface treating agents comprising a trifunctional fluorinated silazane compound and an organopolysiloxane containing a hydrolyzable group such as alkoxy group. However, the hydrolyzable group such as alkoxy group can interfere with cure.
Therefore, an object of the invention is to provide a surface treating agent which has antifouling, water repellent and oil repellent properties and is effectively curable to form an antifouling coating whose surface is tack-free and non-adherent to dust and debris. Another object is to provide a surface treated article.
It has been found that the reaction product obtained by reacting a mixture of an organosilicon compound of the general formula (1) and an organosilicon compound of the general formula (2) with ammonia, or a mixture of the reaction product obtained by reacting an organosilicon compound of the general formula (1) with ammonia and the reaction product obtained by reacting an organosilicon compound of the general formula (2) with ammonia is effective as a surface treating agent. When surfaces of substrates such as glass, glass lenses, mirrors, plastics, plastic lenses, metals, ceramics, porcelain and earthenware are treated therewith, antifouling coatings are formed on the substrate surfaces, which coatings are tack-free, non-adherent to dust and debris, and repellent to both water and oil. 
Herein Rf is a fluorinated organic group of 1 to 12 carbon atoms, R1 is a monovalent hydrocarbon group of 1 to 10 carbon atoms, X is a halogen atom, and xe2x80x9caxe2x80x9d is 0, 1 or 2.
Herein R2, which may be the same or different, is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R3 is a monovalent hydrocarbon group of 1 to 10 carbon atoms which may contain a fluorine atom, R4 is a hydrolyzable group of the general formula (3), R5 and R6 are as defined for R2 or R4, k is an integer of 0 to 100, m is an integer of 0 to 100, n is an integer of 0 to 5, k+m+n is from 0 to 200, with the proviso that the compound of formula (2) contains at least one R4 per molecule. 
Herein R7 is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R8 is a divalent hydrocarbon group of 2 to 10 carbon atoms or oxygen atom, X is a halogen atom, and xe2x80x9cbxe2x80x9d is 0, 1 or 2.
In the first embodiment of the invention, the surface treating agent contains the reaction product obtained by reacting a mixture of (A) an organosilicon compound of the general formula (1) and (B) an organosilicon compound of the general formula (2) with ammonia. 
Herein Rf is a fluorinated organic group of 1 to 12 carbon atoms, R1 is a monovalent hydrocarbon group of 1 to 10 carbon atoms, X is a halogen atom, and xe2x80x9caxe2x80x9d is 0, 1 or 2. 
Herein R2, which may be the same or different, is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R3 is a monovalent hydrocarbon group of 1 to 10 carbon atoms which may contain a fluorine atom, R4 is a hydrolyzable group of the general formula (3), R5 and R6 are as defined for R2 or R4, k is an integer of 0 to 100, m is an integer of 0 to 100, n is an integer of 0 to 5, k+m+n is from 0 to 200, with the proviso that the compound of formula (2) contains at least one R4 per molecule. 
Herein R7 is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R8 is a divalent hydrocarbon group of 2 to 10 carbon atoms or oxygen atom, X is a halogen atom, and xe2x80x9cbxe2x80x9d is 0, 1 or 2.
In formula (1), the fluorinated organic groups represented by Rf are not critical as long as they have 1 to 12 carbon atoms. Typical are perfluoroalkylene groups bound to a silicon atom directly or through an alkylene group. Preferred groups are perfluoroalkylene groups represented by
CpF2p+1CqH2qxe2x80x94
wherein p is an integer of 1 to 8, preferably 4 to 8, q is an integer of 0 to 10, preferably 2 or 3, and p+q is from 1 to 12. Specific examples are CF3xe2x80x94C2H4xe2x80x94, C4F9xe2x80x94C2H4xe2x80x94, C8F17xe2x80x94C2H4xe2x80x94 and C8F17xe2x80x94C3H6xe2x80x94 groups. Examples of the monovalent hydrocarbon groups represented by R1 include alkyl groups such as methyl, ethyl, propyl, butyl and hexyl, alkenyl groups such as vinyl and allyl, aryl groups such as phenyl and tolyl, and aralkyl groups such as benzyl. Of these, methyl, ethyl, propyl and phenyl are preferred, with methyl being especially preferred.
In formulas (2) and (3), the monovalent hydrocarbon groups represented by R2, R3 and R7 are as exemplified for R1. The monovalent hydrocarbon groups represented by R3 may contain fluorine atoms, and such groups correspond to, for example, the foregoing alkyl, alkenyl, aryl and aralkyl groups in which some or all of the hydrogen atoms attached to carbon atoms are substituted with fluorine atoms as well as those groups exemplified for Rf, especially perfluoroalkylene groups of CpF2p+1CqH2qxe2x80x94. Examples of the divalent hydrocarbon groups represented by R8 include alkylene groups such as ethylene, propylene, butylene and hexylene. Exemplary halogen atoms represented by X are chlorine and bromine, with chlorine being especially preferred. Letter k is an integer of 0 to 100, preferably 0 to 50; m is an integer of 0 to 100, preferably 0 to 25; n is an integer of 0 to 5; and k+m+n is from 0 to 200, preferably from 0 to 70.
The organosilicon compound of formula (2) contains per molecule at least one R4, that is, hydrolyzable group of formula (3). The hydrolyzable group may be attached to a side chain or an end of the polysiloxane molecule or both.
Examples of the organosilicon compound of formula (2) are given below. 
Herein, R2, R3, R7, R8, X, k, m, n, and b are as defined above. Preferably b is 0.
Illustrative, non-limiting, examples of the organosilicon compound of formula (2) are given below. 
The mixing ratio of (A) the organosilicon compound of formula (1) and (B) the organosilicon compound of formula (2) is not critical although it preferably ranges from 1:0.1 to 0.1:1, especially from 0.5:1 to 1:0.5 on a weight basis. Outside the range, less amounts of the organosilicon compound of formula (1) may lead to shortage of oil repellency whereas less amounts of the organosilicon compound of formula (2) may result in rather tacky surface coatings. In either case, the desired antifouling property may not be obtained.
In reacting the mixture of organosilicon compounds of formulas (1) and (2) with ammonia, the mixture is previously dissolved in a suitable solvent. The solvent used herein is not critical although solvents containing fluorine atom such as m-xylene hexafluoride, pentafluorodichloropropane and octadecafluorooctane are preferred because of good solubility.
For reaction with ammonia, ammonia gas is blown into the mixture so that ammonia reacts with halogen atoms on the organosilicon compounds of formulas (1) and (2). As to the reaction conditions, at least an equimolar amount to the halogen atoms of ammonia is reacted at room temperature to a temperature below the boiling point of the solvent. Reaction completes within a short time.
At the end of reaction, the resulting ammonium chloride is filtered off. The reaction product is ready for use as a surface treating agent and if desired, after it is further diluted with a solvent as described above.
In the second embodiment of the invention, the surface treating agent contains a mixture of
(Axe2x80x2) the reaction product obtained by reacting (A) an organosilicon compound of the general formula (1) with ammonia, and
(Bxe2x80x2) the reaction product obtained by reacting (B) an organosilicon compound of the general formula (2) with ammonia.
For reactions of components (A) and (B) with ammonia, a method as described above may be employed. The resulting reaction products are admixed to provide the surface treating agent.
The mixing ratio of reaction product (Axe2x80x2) and reaction product (Bxe2x80x2) is not critical although it preferably ranges from 1:0.1 to 0.1:1, especially from 0.5:1 to 1:0.5 on a weight basis. Outside the range, less amounts of reaction product (Axe2x80x2) may lead to shortage of oil repellency whereas less amounts of reaction product (Bxe2x80x2) may result in rather tacky surface coatings. In either case, the desired antifouling property may not be obtained.
The surface treating agent of the second embodiment may also be used as a solution in a solvent as mentioned above.
The reaction product (Axe2x80x2) mainly contains a compound of the general formula (4). The reaction product (Bxe2x80x2) mainly contains a compound of the general formula (5). Also the reaction product of the mixture of components (A) and (B) with ammonia may contain compounds of formulas (4) and (5). 
Herein, Rf, R1 and xe2x80x9caxe2x80x9d are as defined above. 
Herein, R2, R3, k, m and n are as defined above; R9 is a hydrolyzable group of the following formula (6); R10 and R11 are as defined for R2 or R9; with the proviso that the compound of formula (5) contains at least one R9 per molecule. 
Herein, R7, R8 and b are as defined above.
The compounds of formula (5) are exemplified by the following formulas. 
Herein, R2, R3, R8, k, m, n and b are as defined above. Preferably b is 0.
Illustrative, non-limiting, examples of the compounds of formula (5) are given below. 
Accordingly, the invention also provides a surface treating agent comprising the compounds of formulas (4) and (5). The mixing ratio of the compound of formula (4) and the compound of formula (5) preferably ranges from 1:0.1 to 0.1:1, especially from 0.5:1 to 1:0.5 on a weight basis. Outside the range, less amounts of the compound of formula (4) may lead to shortage of oil repellency whereas less amounts of the compound of formula (5) may result in rather tacky surface coatings. In either case, the desired antifouling property may not be obtained. As in the previous embodiments, this surface treating agent may also be used as a solution in a solvent such as fluorine atom-containing solvents.
In the surface treating agent, the concentration of the reaction product of a mixture of components (A) and (B) or the concentration of a mixture of the reaction products of components (A) and (B) may be set as appropriate depending on a particular application method. Usually, a concentration of at least 0.1% by weight, especially at least 0.5% by weight is desirable to achieve satisfactory water repellent, antifouling functions.
Any desired substrate can be treated with the surface treating agent according to the invention. Included are inorganic materials such as glass, glass lenses, mirrors, metals, ceramics, porcelain and earthenware; organic materials such as rubber and plastics; and optical functional materials such as plastic lenses and liquid crystal display filters.
It is not critical how to treat substrates with the surface treating agent. For example, substrates are wiped with fabrics impregnated with the agent. Other useful application methods include brush coating, dipping, spin coating, curtain coating and vacuum evaporation.